Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751191AbdGNS0G (ORCPT ); Fri, 14 Jul 2017 14:26:06 -0400 Received: from mail-it0-f68.google.com ([209.85.214.68]:34974 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750788AbdGNS0F (ORCPT ); Fri, 14 Jul 2017 14:26:05 -0400 From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Fri, 14 Jul 2017 14:25:56 -0400 (EDT) X-X-Sender: vince@macbook-air To: linux-kernel@vger.kernel.org cc: Alexander Shishkin , Ingo Molnar , Peter Zijlstra , Stephane Eranian Subject: Re: perf: bisected sampling bug in Linux 4.11-rc1 In-Reply-To: Message-ID: References: User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 816 Lines: 26 On Fri, 14 Jul 2017, Vince Weaver wrote: > On a good kernel you get the following: > Event perf::instructions with period 1000000 > Event perf::instructions with period 2000000 > fd 3 overflows: 946 (perf::instructions/1000000) > fd 4 overflows: 473 (perf::instructions/2000000) > Ending counts: > Count 0: 946379875 > Count 1: 946365218 > > With the broken kernels you get: > Event perf::instructions with period 1000000 > Event perf::instructions with period 2000000 > fd 3 overflows: 938 (perf::instructions/1000000) > fd 4 overflows: 318 (perf::instructions/2000000) > Ending counts: > Count 0: 946373080 > Count 1: 653373058 additional relevant detail: in the failing case, the group leader of the event set has .pinned=1 If I change that to .pinned=0 then the test passes. Vince